COMMUNITY FORUM

Gas line for LP water heater

I am about to install my second tankless heater. In the instruction manual it lists using copper pipe as an option. What I need to know is will 20' of 5/8" copper be large enough for a gas dryer and the 120K BTU heater? I tried to get 3/4" but all I could find were the connectors that go into the 3/4" BP and the 3/4" pipe coil, but could not find the 3/4" flare nuts or a 3/4" flare tool. I would prefer to install it using the copper since installing black pipe would require taking out everything from the new furnace back to the original fitting, about 30 feet of pipe and fittings since the peopel who installed the original pipes decided to run 80' of pipe making about 4 turns without a union at any point.

I want to say the copper reccomendation was probably for the water, NOT FOR GAS...If there is not a union nearby, you can :shut off the gas,break the union by/in the furnace,flush out the gas pipe.Then you can cut the pipe near the new installion, either thread the new cuts and install a "T" or remove the cut pipes and install new so you can branch off it.If this is too much for you to do, hire a plumber!!! Dont run your gas in copper.

Thank you HKestenholz, that is what I was looking for. I found the pipe, and the fittings for the BP, I just cant find the flare nuts for the pipe. I will measure the tubing I have to find out if it is 5/8" inside or outside, and if it is tinned internally. If it turns out not to be LP compatible, I will probably have to tear down the line from the furnace and plumb it from there, which is going to take longer to get this stuff installed. I only have a 3 day weekend to replace all the plumbing in the house, 150' of main run, plus every sink, toilet, shower, etc, and hookup 2 water heaters. One location has existing gas line, the other doesnt.

BTW I heard that there is a PE plastic gas line that is approved for inside use now, but have not seen it on the market. Any word on that?

OK, checked out the firelog site. Looks like Ineed minimum of 147K BTU capacity, which means I will need 3/4" ID pipe. Looks like I have some shopping to do. That means if I cant find those fittings, I have to take the furnace pipes apart, those were a pain to install the first time around since they go up and over the ductwork between the joists and were installed before the ducts were installed. GRRR.